The present invention relates to a protective housing for a motorcycle drive chain. Most conventional motorcycles sold today utilize an endless chain to transmit power from a drive sprocket mounted on the motorcycle's transmission output shaft to a second sprocket mounted on the rear wheel. These sprockets and drive chain are often not provided with any kind of protective enclosure and, as a result, the chain is exposed to contamination from air, moisture, and dirt. Evaporation of the lubricating oil from the chain into the air, rust caused by the moisture, and increased wear caused by the abrasive effect of the dirt that adheres to the oily surface of the chain all increase the likelihood that the chain will fail under stress. Increased chain wear due to insufficient lubrication is of special consequence with larger motorcycles where new chains cost around $25.00 apiece and must be replaced every 3000 to 6000 miles. If the chain does break during operation, it may be dangerously whipped forward by the drive sprocket with a potential for causing serious injury or damage to the motorcycle operator or engine casing.
In addition, the exposed chain and sprockets are especially hazardous to the motorcycle and passenger, portions of whose anatomy or clothing may become entangled in the running chain and result in serious injury before the motion of the chain can be stopped.
Even when a chain guard is provided, it usually amounts to little more than a thin metal or plastic fender over the topmost portion of the chain. At best, this type of chain guard offers some protection for the operator and passenger against the danger of entanglement in the moving chain or injury from broken chain, but it offers no protection for the chain against insufficient lubrication due to evaporation or contamination from moisture and dirt.